Taking Plan B

Information on how and when to use Plan B

Sometimes women need a birth control backup plan. And when they do, there’s Plan B—the #1 OB/GYN‑recommended emergency contraception brand.

When to use Plan B

Plan B is emergency contraception women can take when:

  • They didn’t use any form of birth control and had unprotected sex
  • There was an issue with their regular birth control method (eg, the condom broke or slipped)
  • They missed a dose (or more) of their regular birth control pill and had sex

Did you know?

Unlike other emergency contraception options, women can use Plan B when they are breastfeeding. In general, no harmful effects of progestin‑only pills like Plan B One‑Step have been found on breastfeeding performance or on the health, growth, or development of the infant. However, random cases of decreased (less) milk production in the mother have been reported.

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How to take Plan B

Plan B emergency contraception helps prevent pregnancy by delaying ovulation. Here’s what women need to know about taking it:

  • It’s a single tablet taken by mouth
  • It must be taken within 72 hours of unprotected sex. The sooner it’s taken, the better it works.
See how Plan B works

Plan B is safe and effective

Plan B contains levonorgestrel—the same active ingredient used in many popular birth control pills—just at a single, higher dose. That said, it shouldn’t be used as regular birth control, and it won’t protect against HIV/AIDS or other STDs.

Some women may experience side effects, including:

  • A period that’s lighter, heavier, early, or late
  • Nausea
  • Lower abdominal cramps
  • Tiredness
  • Headache
  • Dizziness
  • Breast tenderness
  • Vomiting

Potential drug interactions

Some drugs or herbal products that may decrease the effectiveness of progestin‑only pills (such as Plan B) include: barbiturates, bosentan, carbamazepine, felbamate, griseofulvin, oxcarbazepine, phenytoin, rifampin, St. John’s wort, topiramate, and certain HIV/AIDS medications (such as protease inhibitors and non‑nucleoside reverse transcriptase inhibitors).

View drug fact label

Looking for more information?

Our consumer resources page has downloadable content to fit your needs—whether you’re looking for a brochure, ways to save, or a simple fact sheet.

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